Posted by David McCall on 10/12/06 21:30

"Martin Heffels" <feipbjszfo@oxeszdjnlp.xercdpvueppjtmougcqvtz.net> wrote in
message news:134ti2tv2pseckbcaehorm1242q87km6qk@4ax.com...
> On Thu, 12 Oct 2006 15:23:00 GMT, "David McCall" <david_____@techshop.net>
> wrote:
>
>>Film gets by using a 3 bladed shutter (sometimes only 2) to boost the
>>flicker rate,
>>and by bluring the crap out of any motion in the scene to get by at 24P.
>
> Elaborate a bit on this one David. A shorter shutter-time reduces the
> motion-blur. But motion-blur which is already introduced at the recording
> (24 fps), can not be removed, and with a shoerter shutter-time, certainly
> not extended.
>
I'm sorry. I really wasn't clear.
The 3 bladed shutter is in the projector, not the camera.
A camera is in effect a single bladed shutter. Even though
the frame rate is constant, the shutter time is variable.

The maximum shutter time in a typical film camera is 1/24th
of a second minus the amount of time it takes to move the film
to the next frame. I said essentially single bladed because it
only opens once per frame. there are actually what amounts
to 2 blades that overlap to make the opening smaller.

Motion blur comes from something moving while the shutter
is open. The longer the shutter time the more the blur.
Motion blur is your friend. By blurring the motion, it kills
the hard edges that would reveal the low frame rate by
producing annoying jitter.

But you knew all of that anyway. The 3 bladed shutter in the
projector doesn't affect your perception of motion. It alters
the flicker rate to make it fast enough that most people will
accept it as a solid (non flickering) image on the screen.

Perhaps you, like so many people, confuse flicker with jitter.
Jitter is a motion artifact while flicker is a result of the images
being flashed on the screen.

Was that clearer?

David

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